The adoption of photovoltaics for generating electricity from sunlight is strongly impacted by cost considerations. At present, photovoltaic power generation systems are relatively expensive in comparison to conventional fossil-fuel-burning power generation systems in terms of watts produced per dollar required to manufacture, deploy, and maintain such systems. With more specificity, the Watt/dollar ratio for a fossil-fuel burning power generation system is higher than the Watt/dollar ratio for conventional photovoltaic systems. This disparity in cost has prevented wide-spread adoption of photovoltaic power generation systems.
Thin film photovoltaic cells are exemplary cells that can be included in photovoltaic power generation systems. Conventionally, $1/Watt for a cell module is seen as the cost barrier at which photovoltaic cells would achieve cost parity with existing electric grids. While some thin film photovoltaic cells have surpassed this cell module cost barrier, such as, for example, Cadmium Telluride (CdTe) cells, other factors have impeded price parity. For example, persistently low photovoltaic module efficiencies of ˜12% in CdTe cells create balance-of-system issues, which typically raise the implementation cost of photovoltaic power generation systems to as much as 2-4 times the cost of power purchased from existing electric grids despite being manufactured at or below the $1/Watt cell module price point.
While some thin film photovoltaic cells have a high theoretical efficiency, practical performance has remained stagnant. For example, while CdTe cells have an ideal direct band gap of 1.5 eV and are capable of a theoretical maximum single junction conversion efficiency of ˜30%, CdTe cell performance has remained stagnant at ˜16% for the last several years.